1. Field of the Invention
The present invention relates to an apparatus for applying sealant material such as latex or adhesive to the flap closure portion and the adjacent body portion of an envelope whereby when the latex or adhesive portions are placed in overlapping relationship and pressure is applied, the envelope may be sealed.
2. Description of the Prior Art
In U.S. Pat. No. 3,965,851 issued June 29, 1976, an apparatus for applying sealing material to envelopes is disclosed, the patent being assigned to the same assignee as the present application. The apparatus in this prior patent is designed to apply latex or adhesive to the flap closure portion and an adjacent body portion of an envelope. The apparatus disclosed in the patent constituted a significant advance in the art for achieving increased rates of production of applying sealing material to envelopes. In this apparatus, the necessity for the operator to load the blank envelopes into the apparatus at one end of the machine, and then unload the apparatus at the opposite end of the machine, whereby the speed of operation of the machine was determined by the efficiency of the operator in traversing the distance between the opposite ends of the machine, was eliminated. Rather, the envelopes were loaded onto the apparatus at one end, conveyed through the apparatus by overlapping belts which clamped the envelope therebetween and moved them through a latex application station and a drying station and then conveyed them for removal to the same end as the loading end, obtaining increased rates of production not possible theretofore.
The conveyor belts for transporting the envelope through the various stations was arranged in an overlapping triangular configuration. Adjacent the loading end of the apparatus, the overlapping belts were disassociated from each other or split so as to permit the introduction of an envelope therebetween at the commencement of the process. The belts at the loading end of the machine were each twisted about pulleys and rollers perpendicular to their normal plane of travel and separated to enable the introduction of the envelope therebetween and then they are brought back into overlapping relation. The twist implied to each belt places a great deal of strain on each belt causing them to wear more readily. The arrangement further virtually eliminates the overlapping of the belts along one side of the triangular configuration of the apparatus wasting precious space for further treatment of the envelopes, such as drying of the latex or adhesive after it has been applied.